Messages in this thread | | | Date | Tue, 12 Feb 2013 10:58:24 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [tip:x86/mm] x86, mm: Use a bitfield to mask nuisance get_user() warnings |
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On 02/12/2013 10:46 AM, Linus Torvalds wrote: > On Tue, Feb 12, 2013 at 10:25 AM, H. Peter Anvin <hpa@zytor.com> wrote: >> I just thought up this variant, I'm about to test it, but H.J., do you >> see any problems with it? > > Looks good to me. And we already use __builtin_choose_expr(), so it's > "portable". And it should avoid all the potential issues with > bitfields (rmk already pointed out how bitfields don't work well with > the ARM model, who knows what other pitfalls bitfield code generation > could have) > > I wonder if we could/should eventually do some of the sizeof() in > generic code - not have these magic things duplicated in all the > architectures, just have the architectures specify the raw typed > details (__copy_to_user_4() etc). So cross-platform portability could > be a good thing. That's a separate discussion, though, and possibly > not worth it. >
I'm getting rid of the switch statement in the variant that I'm currently testing, so that would probably be undesirable.
-hpa
-- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
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